Preparation of electrotype-molds.



ALBERT W. HARRISON, OF BALTIMORE, MARYLAND.

PREPARATION OF ELEGTROTYPE-HOLDS. 3

Specification of Letters Patent.

' Application fled July 1c, 1900. am No. 826,438.

To all whom it may concern:

Be it known that I, ALBERT W. HARRISON, a citizen of the United States, residing at Baltimore city, in the State of Maryland, have invented certain new and useful Improvements in the Preparation of Electrotype Molds, of which the following is a specification.

My invention has for its object the preparation of molds for electrotypes in an improved manner whereby the usual troublesome time-consuming steps heretofore considered necessary in reparing the molds for the electrolytic batli are rendered unnecessary and are entirely dispensed with.

With this object in view, my invention consists in a new and improved com osition or solution with which such mo ds are treated during such preparation, all as hereinafter fully described and afterwards specifically claimed.

It is well known that when wax molds, treated with graphite are placed in an electrolytic solution and a de osit of copper or other metal made upon t e surface of the mold, the action is at first slow and confined to particular parts of the surface, thereby requiring in some cases several hours to produce a uniform and unbroken metallic covering throughout the whole extent of the mold. .It also sometimes happens that the graphite or metallic oxid does notperfectly adhere to the'wax surface of the mold, and consequently the deposit is not uniform. These defects are removed by the use of my improved solution in the process of preparing electrotype molds, and the deposit is caused to take place uniformly over the whole surface of the mold immediately upon the immersion of the latter in the electrolytic solution, thus saving many hours in the production of a late, and insuring a deposit of uniform thickness.

The following is a sufficiently minute description of the mode of proceeding to enable others skilled in the art of roducing electrotype molds to practice 1 1y invention.

In preparing my new and improved composition or solution I take the following ingredients in the proportions named or suberal salt and stantially in said proportions, to wit 1 gallon of water 11} lbs. of graphite 1 oz. minthoroughly mix together in any suitable receptacle.

The mineral salt which I prefer is kainit but many other mineral salts may be used with more or less success, provided only that Patented Oct. 27, 1908.

oz. metallic powder which I- it be a salt of a mineral having a lower conductivity than the metallic base-of the salt of the electrolyte, and while I prefer bronze copper for the metallic powder, I may use others if so desired.

After the mold is formed in the usual, or any suitable manner, it is suitably placed so that my new and improved solution may be applied to its surface eitherby sprinkling, pouring, pumping or by any approved or suitable means. This application of my composition or solution to the surface of the mold produces a metallic conductive surface thereon upon which the electrolytic deposit is laid in the usual manner and I find the conductive surface thus produced to be superior to that produced by any process with which I am familiar.

In thus preparing electrotype molds, I do away entirely with the old methods, such as dry polishing by machines and oxidizing the molds by the use of iron filings and sulfate of copper after dry polishing with graphite and l find my process to be a great improvement in the saving of time and expense and the production of a vastly superior result.

The mold treated with my solution is subjected to the electrolytic bath in the usual manner.

\Vhat I claim as new is y 1. The herein described solution for use in preparing electrotype molds, for the electrolytic bath, containing the ingredients specified and substantially in the proportions named, comprising one (1) gallon ot' water, and one (1) ou11 -e of a mineral salt, of a mineral having a lower conductivity than 1the metallic base of the .salt of the electrote. 2. The herein described solution for use in preparing electrotype molds for the electrolytic bath containing the ingredients specilied and substantially in the proportions named, comprising one (1) gallon of Water, undone (1) ounce of kainit.

3. The improved solution for use in preparing molds for electrotypes for the electrolytic bath which consists of substantially one (1.) gallon of Water, one (1) ounce of a salt of a mineral having a lower conductivity than the metallic base of the salt of the electrolyte, and a small quantity of graphite.

In testimony whereof I afiix my signature in presence of two witnesses.

ALBERT \V. HARRISON. \Vitnesses:

ANDREW S. MoNmm, CIIAs. E. Himmsox. 

